It's unlikely that they're going to let us change these rules based on this (brand new) site asking for it, since these restrictions are the same network-wide.
It shouldn't be hard to write 10 characters to describe your edit. As for the restriction that the edit must have at least 6 characters, this is largely because edits by users without enough rep, are generally expected to be more substantial than just changing one word. Editing a post will bump that post up to the top, and make other (possibly unanswered and therefore more important to some people) posts less likely to be seen, it can be seen as a "cheap" way to earn reputation without knowing anything about the site's subject, and it will cause more work to be done by reviewers, so if you don't have enough rep to edit a post, it generally should be more than just a one-word change.
In the example you gave, where "straightforward" was spelled wrong, earlier in the same answer, "regulate it block production" should have said "regulate its block production". In my experience network-wide, when there's one typo that's severe enough for me to want to correct it, there's usually (not always, but usually) at least one other thing that also needs correction, and this was indeed the case this time.